Sex Quiz - Can't Cum.

Sorry but this sex quiz got me fucked up with question 3. Is there anyone else who just can't cum from doggy style? I get really frustrated during sex actually. My SO can cum so easily. Especially during doggy and I just can't. I'm fat and I'm sitting there tryna flick the bean from underneath myself with my ass in the air while being pounded and he's just like "I'm fucking you so hard. Why can't you cum??" And I'm like "Yeah man. I'll let you know when I figure it out." Anyone else? COMMENTS PLEASE!!!!!